This invention relates to the conveying of fish. German Offenlegungsschrift No. 1936653 discloses a device for processing fishes to form fillets and in which a fish, placed on its back on a flat V-shaped table and having its tail fin and dorsal fin centred in a longitudinal groove disposed in the said table, is pushed manually tail first beneath a cover of inverted V-shaped cross-section and subsequently between two double cone wheels which convey the fish under a fork and then against two knife systems. Each of the double cone wheels comprises two pairs of truncated cones which counter-rotate about vertical shafts, the upper pairs tapering downwardly and outwardly and enclosing an acute angle between them, the lower pairs being constructed as discs the edge of which include an angle of approximately 90.degree. between them in the upward and outward direction. This device suffers from the disadvantages that gaps remain between all the cone wheels so that continuous guiding action is not obtained and that the surface enclosed when the cone wheels are completely advanced towards each other is far too large to be able to centre, guide and align the tail root region or the tail fin of a fish.